2,549 research outputs found
Transverse single-spin asymmetries in proton-proton collisions at the AFTER@LHC experiment
We present results for transverse single-spin asymmetries in proton-proton
collisions at kinematics relevant for AFTER, a proposed fixed-target experiment
at the Large Hadron Collider. These include predictions for pion, jet, and
direct photon production from analytical formulas already available in the
literature. We also discuss specific measurements that will benefit from the
higher luminosity of AFTER, which could help resolve an almost 40-year puzzle
of what causes transverse single-spin asymmetries in proton-proton collisions.Comment: 10 pages, 4 figures; more details/discussion added to the text,
references added/updated, version to appear in Advances in High Energy
Physics for the Special Issue "Physics at a Fixed-Target Experiment Using the
LHC Beams
A_{LT} in the Nucleon-Nucleon Polarized Drell-Yan Process
We present a leading order (LO) estimate for the longitidinal-transverse spin
asymmetry (A_{LT}) in the nucleon-nucleon polarized Drell-Yan process at RHIC
and HERA- energies in comparison with A_{LL} and A_{TT}. A_{LT}
receives contribution from g_1, the transversity ditribution h_1, and the
twist-3 distributions g_T and h_L. For the twist-3 contribution we use the bag
model prediction evolved to a high energy scale by the large-N_c evolution
equation. We found that A_{LT} (normalized by the asymmetry in the parton
level) is much smaller than the corresponding A_{TT}. Twist-3 contribution
given by the bag model also turned out to be negligible.Comment: Talk presented at the KEK-Tanashi International Conference "Physics
of Hadrons and Nuclei", Dec. 14-17, 1998, Tokyo. 4 pages in Latex. 1 figure
included as eps files using epsbox.st
A small and light weight heat exchanger for on-board helium refrigerator
A small and light weight heat exchanger used for small helium refrigerator has been developed by Sumitomo Heavy Industries, Ltd. This heat exchanger is a laminated metal heat exchanger which consists of perforated aluminum metal plates and glassfiber reinforced plastic separators. The size is from 100 mm to 28 mm in diameter and about 300 mm in length. The weight is from 2.5 kg to 0.6 kg. Also it can be used between room temperature and liquid helium temperature. The thermal efficiency obtained has been more than 96%. The heat exchanger has been practically used for on-board helium refrigerator in Japanese National Railways' superconducting magnetic levitated trains
Twist-3 approach to single transverse-spin asymmetry
We study the single transverse-spin asymmetry for the inclusive direct-photon and single-jet productions in the proton-proton collision based on the twist-3 mechanism in the collinear factorization. Taking into account all the effects from the twist-3 quark-gluon correlation functions inside a transversely polarized proton, we present a prediction for the asymmetries at the typical RHIC kinematics. In both processes we find sizable asymmetries in the forward region of the polarized proton while they are almost zero in the backward region. This implies that if one finds a nonzero asymmetry in the backward region in these processes, it should be ascribed wholely to the three-gluon correlations
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